Patent GB-700614-A (GB)
Title: Improvements in or relating to photographic cameras
IPC: G03B17/42
Filed: 1950-06-22
Abstract: 700,614. Photographic cameras. COLLINGS, C. E. HILLARY-, and PETTIFER, F. J. June 20, 1951 [June 22, 1950], No. 15614/50. Class 98(1) The camera comprises a casing, film feed mechanism, a shutter, and mechanism such as a spring motor for driving the film feed mechanism and operating the shutter, the film feed mechanism including a member arranged for translatory motion within the casing for bringing successive frame areas of the film into the image gate consequent upon a single operation of a release for actuating the drive mechanism, and means operatively connecting the shutter and the film feed mechanism so that, following each motion of the feed member, the shutter is operated, the shutter including trip mechanism providing a predetermined variation in the duration of the successive exposures effected after each single operation of the release. As shown in Fig. 4, the camera has an outer top plate 17 spaced from an inner plate 18. The main spring 13 is housed in a drum 14 projecting through plate 17 and having winding projections 14<SP>1</SP>, one end of the .spring being fixed to the drum and the other to a stud 15 fixedly mounted on plate 18 and on which drum 14 is journaled. The toothed lower periphery of drum 14 meshes with a gear wheel 21 which is fast with a gear wheel 31 engaging a pinion 32 operating an exposure counter, and with a wheel 23 driving a disc 24 rotating in a recess in plate 18. A bent lever 11, Fig. 5, is pivoted at 28 to disc 24 and has a pin 26 at its elbow engaging a slot 27 in the plate. The shape of the slot is such that a claw 11<SP>1</SP> at the end of the lever moves in a D-shaped path, having a straight portion over which the claw engages a perforation in the film to advance it by one frame, and a curved portion over which it returns out of engagement with the film. Claw 11<SP>1</SP>, in the straight part of its path, also engages two sliding plates 4, 5 of a sliding plate shutter, and moves them against the action of their respective springs into the position shown in Fig. 8, wherein their rectangular apertures 4a, 5a, are out of register. When claw 11 is retracted plate 4 returns, plate 5 being held by the end of a lever 12 which engages a projection 5b thereof, so that apertures 4a, 5a register to make an exposure until plate 5 is released. Lever 12, Fig. 6, is pivoted at 12<SP>1</SP> to plate 18 and has a second arm 12f the turned-over end 12c of which is spring-urged into engagement with a cam 30 on a boss of the drum 14. The cam has e.g. three crests 30<SP>1</SP> which rock lever 12b to free plate 5 and terminate the exposure. The crests are so spaced that. for one revolution of the cam, three exposures of different durations are made, the film being shifted three frames. In this case the gear ratio between the drum and pinion 21 is 3: 1, but by making the ratio e.g. 3.2:1 successive revolutions of the drum may take place, giving a succession of exposures of progressively varying duration. When the spring 13 is wound by turning drum 14 by means of projections 14<SP>1</SP>, pinion 31 is rotated, and a stop spring 40, Fig. 4, thereon clicks over a projection 24a mounted on disc 24. The number of clicks indicate the number of exposures which will be made on release. After winding,. disc 24 is held by a lever 34, Fig. 6, urged by a spring 35 into the path of a projection on the disc. On pressing the release knob, a plunger bears on a lug 10 formed on lever 34 to rock the lever and release the mechanism, which effects the required number of exposures as outlined above until it is brought to rest by the abutment of projections 41, 42 on pinion 40 and on drum 14 respectively. Specification 695,285 is referred to.